1. Field of the Invention
The subject application generally relates to a mobile device, and more particularly, relates to a mobile device comprising a tunable antenna.
2. Description of the Related Art
With the progress of mobile communication technology, portable devices, for example, notebook computers, tablet computers, mobile phones, multimedia players, and other hybrid functional portable devices, have become more common. To satisfy the demand of users, portable devices usually can perform wireless communication functions. Some devices cover a large wireless communication area, for example, mobile phones use 2G, 3G, LTE (Long Term Evolution) and 4G systems and use frequency bands of 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, 2300 MHz, and 2500 MHz. Some devices cover a small wireless communication area, for example, mobile phones use Wi-Fi, Bluetooth, and WiMAX (Worldwide Interoperability for Microwave Access) systems and use frequency bands of 2.4 GHz, 3.5 GHz, 5.2 GHz, and 5.8 GHz.
However, there is usually extremely limited space in portable devices, such as a mobile device. It is a critical challenge for antenna designers to design antennas of a mobile device to operate in multiple bands without increasing the antenna size.